10/30/22, 5:13 PM L9: Reproductive Number R0 : Network Science – CS-7280-O01
L9: Reproduc ve Number R0
Epidemiologists often use the “reproductive number”, R0, which is the average number of secondary infections that arise from a single infected individual in a susceptible population.
One way to estimate R0 is to multiply the average number of contacts of an infected individual by the probability that a susceptive individual will become infected by a single infected individual (“attack rate AR”). So, the R0 metric does not depend only on the given pathogen – it also depends on the number of contacts each individual has.
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If the number of secondary infections from a single infected individual is R0>1 then an outbreak is likely to become an epidemic, while if R0<1 then an outbreak will not spread beyond a few initially infected individuals. In the context of the SIS and SIR models, we can easily show that the reproductive number R0 is equal to the ratio . https://gatech. instructure. com/courses/265324/pages/l9-reproductive-number-r0?module_item_id=2520742 1/2 10/30/22, 5:13 PM L9: Reproductive Number R0 : Network Science - CS-7280-O01 The Reproduc ve Number for Common Infec ous Diseases Influenza (1918 strain) Transmission Airborne droplet Social contact Fecal-oral route Airborne droplet Airborne droplet Sexual contact Airborne droplet Airborne droplet for some common infectious The table shows the estimated reproductive number diseases. Note that R0 also depends on the number of contacts -- and so this metric can vary with time because of interventions such as quarantines, social distancing, or safe- sex practices. The estimates shown in this table should be interpreted as typical values in the absence of such interventions. Regarding COVID-19, the debate about its actual R0 is still raging. The first reported result from Wuhan, China was that R0=2.2 – based on direct contact tracing. As of July 2020, there are estimates in the literature that vary from 2.0 to 6.5. Food For Thought Show that in the SIS and SIR models the reproductive number R0 is equal to the ratio . https://gatech. instructure. com/courses/265324/pages/l9-reproductive-number-r0?module_item_id=2520742 2/2 程序代写 CS代考 加微信: powcoder QQ: 1823890830 Email: powcoder@163.com